OBJECTIVE： To analyze and compare the cost-effectiveness of domestic and imported imipenem and cilastatin sodium for severe lower respiratory tract infection. METHODS： In retrospective study， 57 cases of severe lower respiratory tract infection receiving imipenem and cilastatin sodium were selected and divided into domestic group （30 cases） and imported group （27 cases）. Clinical efficacy and ADR were compared between 2 groups， and pharmacoeconomic principle was used to analyze the cost-effectiveness of 2 therapy plans. In the study， the cost only included drug cost of apatient in each group for a treatment course. RESULTS： The cost of domestic group and imported group were 1 833.90 yuan and 2 373.90 yuan， and the effective rates were 80.00％ and 92.59％， with statistical significance （P＜0.05）； the incidence of ADR were 26.67％ and 18.52％ there was no statistical significance between 2 groups （P＞0.05）. The cost-effectiveness ratio （C/E） of 2 groups were 22.92 and 25.64，and the incremental cost-effectiveness ratio（ΔC/ΔE） was 42.89. Those of sensitivity test were 20.63 and 23.07， ΔC/ΔE was 38.60， which was consistent with the result of cost-effectiveness analysis. CONCLUSIONS： In the treatment of severe lower respiratory tract infection， domestic imipenem and cilastatin sodium shows economic advantage. Imported imipenem cilastatin sodium is better than domestic one in therapeutic efficacy. Drug should be selected according to the condition of patients.